As is known, in order to ensure the safety of the operators and the integrity of all apparatuses with high absorption levels, an interlocked socket incorporates a locking device, of a mechanical or electrical type or a combination thereof, which is connected to an electric circuit breaker, which is constituted very often by a rotary switching apparatus, in order to ensure that the plug cannot be inserted or removed in the presence of voltage.
Conventional interlocked sockets generally have considerably larger dimensions than simple sockets having similar electrical characteristics, in order to be able to accommodate the breaker of the electric circuit, the member for actuating it and the device for the mechanical locking of the plug.
GB208081 discloses a plug connector combined with an electric switch. Two contact carrying discs are coupled together on inserting the plug which latter is turned to close the circuit and retained in this position by a detent engaging a pin of the plug; upon withdrawing the plug the lower disc is released and opens the circuit and the detent and upper disc are then released in turn. The plug has three pins, one longer than the others. The pins enter bushed holes in an upper disc carrying contact arms in connection with the bushes and normally pressed into two spring jaws on a second disc. The pin enters a hole in the disc and when the plug is turned both discs are carried around so that contact blades connected to the contact jaws on the disc are inserted into terminal jaws on the base and close the circuit. Springs controlling each disc are strained in this movement and a spring controlled detent on a part and arranged between the discs engages the pin and locks it and the discs against rotation.